Restore to Factory Defaults
On completion, do a Restore from backup.
As the Contact button is part of the iOS, it will be replaced by the process, along with all your contacts
Just got an iPhone 4S and have been downloading much stuff. One item was contacts, which I had the icon on the screen. But now I've downloaded my contacts, the icon has disappeared. I don't want to revert to original settings and lose all the other items I've downloaded, but I'd like to see that Contact icon back on screen. Suggestions?